I know it sounds a bit of a cliche but I have been growing cornish crosses for 6 weeks now. The average weight is about 5.5 pounds currently. I have been weighing them every week now. I spoke to a someone last night on the phone and he told me that I will never reach a goal weight of 9 pounds. He said I will need a Plymouth Rock that will need to be fed for at least 62 weeks. Is this at all true. I have seen on feathersite.com Cornish crosses reach a weight of 20 pounds. Will my Cornish Crosses reach a goal weight of 9 pounds and by what age!